CT Chokes

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Do It Yourself (DIY) paradise for tube and SET project builders.

Hey-Hey!!!,
I had a few discussions with MQMike after posting the frequency response of a simple CT choke I had made. We settled on a simple interleave, distributing ~50% of each bay to the other side and layering it between the other coil. My simple one had about 6% leakage inductance between halves, which yeilded a resonance right in the middle of the midrange and fell off beyond that. The interleaved one had .08% leakage between coils. Now these were not the same core, and mine was about 3x the inductance of Mike's to start with, so it is not quite an apples-apples comparison.
anyway, Mike sent me a sample, of a CT choke, similar to the EXO-173, wound on a two bay bobbin with the simple interleave, and it worked well as both a phase splitter(the 180 leg was +1.1 dB at 20kcps), and as a 2:1 step up autoformer( +.48 dB at 20kcps). Just for reference, this is comparable performance to a UTC A-18, and better than the Triad HS27 in phase inverter duty. No resosnances or peaking in the audio, just an slight up-turn at the end, which might be addressed with a properly selected loading scheme.
regards,
Douglas

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The Cable Cooker

Topic - CT Chokes - Sector-7G 19:32:00 02/24/04 (1)

HS-27 - MQracing 20:11:38 02/24/04 (0)

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